Sturge-Weher Disease: Operative Indications and Surgical Results Masanori Ito, MD, Kiyoshi Sato, MD, Akira Ohnuki, MD and Akira Uto, MD
Patients with Sturge-Weber disease with epilepsy refractory to medical therapy have been reported to develop slowly progressive neurological deficits and ultimately become moderately or severely disabled. We studied six patients with Sturge-Weber syndrome including its incomplete form. Three out of six patients with Sturge-Weber syndrome revealed evolution of calcified angioma on computed tomography. All of the three cases developed medically intractable seizures. Total and/or subtotal hemispherectomy was performed for these three cases. The surgery was effective for controlling seizures in all three cases except one with infantile spasm with hypsarrythmia on electroencephalogram who is still on anticovulsant. Although the unremitting deterioration in mental retardation and hemiparesis was not effectively prevented by the surgery possibly because the timing of surgery was delfl)'ed in one case, the surgery not only stopped the frequent medically-intractable seizures, but also dramatically prevented the psychomotor deterioration in the other case. Although the role of surgical treatment for the patients with Sturge-Weber syndrome remains poorly defined, one can expect excellent results if the indications for surgery are carefully analyzed and hemispherectomy is performed on an individual basis. Key words: Sturge-Weber disease, convulsive seizure, calcification, cerebral angioma, hemispherectomy. Ito M, Sato K, Ohnuki A, Uto A. Sturge- Weber disease: operative indications and surgical results. Brain Dev 1990;12:473-7
Although little is known of the clinical course and longterm prognosis of Sturge-Weber disease, it has been reported that about 30 to 40% of patients develop slowly progressive neurological deficits, and ultimately become moderately or severely disabled [1, 5, 7-9]. The deleterious effect of repeated seizures and chronic cerebral ischemia caused by cerebral angiomatosis on the developing brain is thought to be the underlying pathophysiology of the disease [7]. Neurosurgical intervention for the disease has been advocated in several institutions to control the intractable seizures and prevent the development of progressive neurological deficits [1,5,7-9]. We recently performed hemispherectomy in three patients with Sturge-Weber disease. In this paper, we discuss the operative indications and surgical results with respect to the natural history and outcome of the disease, and present
From the Department of Neurosurgery, J untendo University School of Medicine, Tokyo. Received for publication: February 17, 1990. Accepted for publication: May 9, 1990. Correspondence address: Dr. Masanori Ito, Department of Neurosurgery, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113, Japan.
an illustrative case.
PATIENT SELECTION AND SURGICAL INDICATIONS The neurological and radiological fmdings of six patients with Sturge-Weber disease are listed in Table 1. Neurosurgical intervention was not indicated for those in whom the convulsive seizures were being medically controlled, psychomotor development was not retarded, and no progression of calcified lesion was found on CT (patients 1, 2 and 3). We carried out surgical treatment for three patients (patients 4, 5 and 6) who were medically intractable and had psychomotor retardation. A 6-month-old male infant with Sturge-Weber disease (patient 4) [10] had intractable seizures and right hemiparesis for three months. On CT, the patient had cerebral atrophy and a calcified lesion in the left parieto-occipital lobe. The patient underwent excision of the lesion, by parietooccipital lobectomy. However, seizures could not be controlled postoperatively, and progression and extension of the calcified angiomatosis were observed on CT at 11 months of age. Therefore, left hemispherectomy was performed. A 3-month-old male infant (patient 5) with facial angioma at birth presented with infantile spasms
occasionally associated with tonic-clonic seizures. Compared with the CT finding at birth, CT showed progression of a band-like calcified lesion along the right frontal gyrus and frontal cortical atrophy. The seizures were not controlled by an exhaustive anticonvulsant regimen, and neck
Table I
fixation began to be impaired. A 5-year-old boy with atypical Sturge-Weber disease [11] (patient 6) underwent right subtotal hemispherectomy. The clinical course and surgical result of this patient are described separately as an illustrative case report.
Clinical data Age
Sex
Facial angioma
Onset
Seizure type
Response to medication
Neuro· logical deficit
1
8m
M
L
7m
Focal
Controlled
None
2
10m
M
R
10m
Focal
Controlled
3
3m
F
None
3m
Focal, IS
4
5m
M
L
3m
5
2m
M
R
6
4y
M
None
Patient
CT calcifications
CT atrophy
CT evolution
L-focal, spike
L-O
None
No
3
None
R-focal, negative spike
R&L-O
None
No
1.5
Controlled
None
RL polyspike& wave
R&L-PO
Lt-T,P
No
3
Focal
Intractable
Hemiparesis, psychomotor retardation
L-diffuse, slowing
L-F,T,P,O
Lt-F,T
Yes
6
3m
IS,focal
Intractable
Poor head fixation
Hypsarrhythmia
R-F
R-F
Yes
1.5
3y
Focal
Intractable
Psychomotor retardation
R-diffuse, spike wave
R-T,P,O
R-T,P,O
Yes
3
EEG
Follow· up (years)
m: months old, y: years old, M: male, F: female, L: left, R: right, IS: infantile spasm, F: frontal, T: temporal, P: pariental, 0: occipital.
Fig 1 Precontrast CT at 3 years of age shows a serpentine calcification in the right occipitallobe.
Fig 2 Precontrast CT scan at 4 years of age demonstrates extension of the calcified lesion the into temporal and parietal lobes. Note the enlargement of the trigone and inferior hom of the right lateral ventricle.
474 Brain & Development, Vol 12, No 5,1990
RESULTS Hemispherectomy or subtotal hemispherectomy was apparently effective for the control of medically intractable seizures in all three cases. The seizures disappeared postoperatively in all patients, and anticonvulsant administration has not been needed except in patient 5, who recently underwent surgery. Psychomotor retardation following onset of seizures was dramatically reversed immediately after subtotal hemispherectomy concomitant with the disappearance of seizures in two cases (patients 4 and 5). However, in patient 3, progression of mental retardation and loss of the motor function of the right fmgers and hand could not be prevented by the surgical management, probably because the patient already had right hemiparesis and cerebral atrophy, as shown by CT at 4 months of age.
motor development until the onset of convulsive seiZUres at 3 years. By age 4, the seizures had become increasingly intractable in spite of exhaustive anticonvulsant regimens. The patient was suffering convulsive attacks several times a day by 5 years of age, and during the one-year period, had become unable to sing, run, or count. Precontrast CT at 3 years of age revealed a typical fmding of Sturge-
ILLUSTRATIVE CASE REPORT A 3-year-old boy had shown completely normal psycho-
Fig 3 Axial MR image (SE 500/30) showing marked dilatation of the trigone and inferior horn of the right lateral ventricle.
Fig 4 Axial MR image (SE 2000/80) showing an area of high signal intensity in the thinned right tempordparietooccipitallobe. Note the signal intensity of the lesion is almost identical with that of cerebrospinal fluid.
Fig 5 A: Intraoperative photograph showing leptomeningeal angiomatosis in the right frontoparietal cortex after aspiration of cerebrospinal fluid from the dilated subarachnoid space. Band C: Photomicrographs of occipital cortical tissue showing extensive leptomeningeal angiomatosis and calcifications within the brain parenchyma. HE stain, x 50 (B) and xl 00 (C).
Ito et al: Sturge-Weber 475
Weber disease (serpentine calcified lesion) in the right occipital lobe (Fig 1). The lesion was not enhanced by contrast medium. Since the patient did not have facial angioma, he was diagnosed as having Sturge-Weber disease without facial nevus [11] or a form fruste variety of the disease. Precontrast CT at 4 years of age demonstrated extension of the calcified lesion into the temporal and parietal lobes concomitant with enlargement of the trigone and inferior horn of the right lateral ventricle (Fig 2). Tl-weighted MRI revealed marked dilatation of the trigone and inferior horn of the right lateral ventricle, while the T-2 weighted image showed an area of high signal intensity in the right temporoparietooccipitallobe, suggesting ischemic change in this region (Figs 3 and 4). Right carotid angiography revealed an avascular area and a lack of cortical vein visualization in the right temporoparietooccipital region. There was no visualization of deep veins such as the internal cerebral vein, basal vein, and vein of Galen. [1 23 I] IMP-SPECT revealed a marked reduction in blood flow in the right temporoparietooccipital lobe, corresponding to the area of high signal intensity signal on the T-2 weighted MRI image. Right temporoparietooccipital lobectomy, subtotal hemispherectomy, was carried out. The frontal lobe, thalamus, and basal ganglia were preserved. The postoperative course was uneventful. The patient has been free of seiZUres without the administration of anticonvulsants. Three months after the operation, the patient was able to sing, count, and run, and started going to Kindergarten. The intraoperative fmdings of patient 5 are shown in Fig 5A. After the cerebrospinal fluid was aspirated, the distended subarachnoid space collapsed and leptomeningeal angiomatosis was .observed in the atrophic right frontoparietal cortex. Histological fmdings of the case are shown in Fig 5B and C. There was extensive leptomeningeal angiomatosis and calcification within the brain parenchyma, both in the cortex and white matter. Neuronal atrophy, neuronal loss and gliosis were also found. DISCUSSION Natural history of Sturge-Weber disease The natural history of Sturge-Weber disease remains unknown. Long-term follow-up studies reported from the Mayo Clinic (31 cases) [8] and the Hospital for Sick Children in Toronto (41 cases) [9] indicated that 30 to 40% of patients with the disease had moderate to severe neurological deficits and epilepsy, and did poorly at home or were confined to institutions. It deserves special mention that patients in whom the onset of convulsive seizures was within the first year of life had severe neurological deficit [7, 9]. Nevertheless, variability in natural course of the disease has been reported such as delayed onset of neurological signs [6], and delays onset of sei-
476 Brain & Development, Vol 12, No 5,1990
zures at the age of 4 years which became refractory to medical therapy with marked visual symptomatology at 13 years of age [2]. Progressive nature of the disease Progressive calcification in the disease is thought to be caused by reduced blood supply to the involved hemisphere, which in turn leads to gliosis and atrophy of the brain parenchyma induced by chronic ischemic insult [7, 12]. The repeated convulsive seizures, which implicate abnormal excitation of the neural cells and relatively poor blood supply (pathologically enhanced energy consumption), may result in neuronal damage similar or identical to ischemic brain damage [13]. It is well-known that tram-track calcification on plain skull X-ray films usually appears in patients over the age of 2 years and is rarely demonstrated before the age of one [14], indicating the progressive nature of brain calcification. Serial CT has been reported to demonstrate evolution of calcified occipitallesion [2]. Progressive enlargement of the calcified lesions was clearly demonstrated on CT scan in three of our six cases. All three of these patients presented with medically intractable seiZUres. In contrast, the calcified lesions remained unchanged during at least one to two years of follow-up in the three patients in whom seizures were medically controlled. Positron emission tomography (PET) with 2-deoxy-2 [18] fluoro-D-glucose to measure local cerebral glucose metabolic rates for glucose [4] and/or 133-Xe single photon emission computed tomography (SPECT) to measure regional cerebral blood flow [3] have been suggested to reveal functional abnormalities that precede structural changed detected by CT in patients with Sturge-Weber syndrome. Subsequently, serial PET or SPECT studies can be used to assess the progression of functional cerebral impairment [3, 4] . Rationale for surgical treatment It seems reasonable to expect that surgical removal of the
leptomeningeal angiomatosis and underlying abnormally functioning gliotic cerebral cortex would eliminate the ischemic epileptic focus and prevent progression of ischemic convulsive brain damage [1, 5, 7, 8]. Hoffman et al [7] reported the results of seven hemispherectomies for infants with Sturge-Weber disease. They postulated that hemispherectomy must be undertaken if seizures begin in infancy, the disease is Unilateral, and the entire hemisphere is involved. Based upon their follow-up results for one to 13 years (median eight years), the younger the patient at the time of surgery, the higher the eventual IQ; in addition, an inverse correlation was noted between the duration of preoperative seizures and postoperative IQ [7]. Surgical treatment should be undertaken before irreversible organic brain damage develops. Early surgical intervention is strongly advocated if the epilepsy is considered to be medically intractable. Hoffman et al
[7] claimed that infantile cases presenting with intractable seizures should be operated on within the first year of life. In our case of rather late onset, subtotal hemispherectomy case, in a 4-year-old male (patient 6) was able to abolish intractable seizures and even reverse severe psychomotor retardation. Surgical method and results According to Falconer et al [5], Balder pioneered surgical intervention for cerebral angioma in the disease, and electrocoagulation of angiomatosis is reported to reduce the frequency of convulsive seizures. Peterman et al [8] reported that one of their four surgically treated patients showed an apparent increase in intelligence quotients after surgical excision, and seizures and behavioral problems decreased. Falconer and Rushworth [5] reported the results of five hemispherectomies for the disease, and concluded that surgery helped to abolish seizures. Hoffman et al [7] reported that hemiparesis in children operated upon early in infancy was surprisingly minimal. The late postoperative complication of superficial cerebral hemosiderosis due to repeated bleeding caused by a lack of adequate support for the remaining hemisphere is reported to develop in one-fourth to one-third of patients followed for long periods after an anatomically complete hemispherectomy [15]. However, this complication could be prevented by subtotal hemispherectomy, leaving in place the frontal and occipital lobes. In the present cases, parts of the frontal or occipital lobes were left unremoved. The area to be removed was determined by neuroimaging, i.e., a calcified lesion on CT, an area of low or no blood flow on SPECT or PET, and a high intensity area on T-2 weighted MRJ image, and the intraoperative macroscopic (microsurgical) appearance.
REFERENCES 1. Alexander GL. Sturge-Weber syndrome. In: Vinken PJ, Bruyn GW, eds. Handbook of clinical neurology. Vol 14. Amsterdam: North-Holand, 1970:223-40. 2. Bye AA, Matheson JM, Mackenzie RA. Epilepsy surgery in Sturge-Weber syndrome. Aust Paediatr J 1989; 25: 103-5. 3. Chiron C, Raynaud C, Tzourio N, et al. Regional cerebral blood flow by SPECT imaging in Sturge-Weber disease: an aid for diagnosis. J Neurol Neurosurg Psychiatry 1989;52: 1402-09. 4. Chugani HT, Mazziotta JC, Phelps ME. Sturge-Weber syndrome: a study of cerebral glucose utilization with positron emission tomography. J Pediatr 1989; 114:244-53. 5. Falconer MA, Rushworth RG. Treatment of encephalotrigeminal angiomatosis (Sturge-Weber disease) by hemispherectomy. Arch Dis Child 1960;35:443-7. 6. Gilly R, Lapras C, Tommasi M, et al. Maladie de SturgeWeber-Krabbe. Pediatrie 1977;1:45-64. 7. Hoffman HJ, Hentrick EB, Dennis M, Armstrong D. Hemispherectomy for Sturge-Weber syndrome. Child's Brain 1979;5:233-48. 8. Peterman AF, Hayles AB, Dockerty MB, Love JG. Encephalotrigeminal angiomatosis (Sturge-Weber disease). JAMA 1958; 167:2169-76. 9. Tsuchida T, Hoffman HJ, Hendrick EB, Thompson H. Sturge-Weber syndrome. A clinical study of 41 cases of 153 facial hemangiomas (in Japanese). No to Shinkei (Tokyo) 1980; 32:949-56. 10. Ito M, Sato K, Maruki C, Nitta T, Ohnuki A, Ishii S. Surgical treatment of Sturge-Weber syndrome - case report. Neurol Med Chir (Tokyo) 1989;29:60-4. 11. Ambrosetto P, Ambrosetto G, Michelucci R, Bacci A. SturgeWeber syndrome without port-wine nevus. Report of 2 cases studied by CT. Child's Brain 1983; 10: 387-92. 12. DiTrapani G, DiRocco C, Abbamondi AL, Caldarelli M, Pocchiari M. Light microscopy and ultrastructural studies of Sturge-Weber disease. Child's Brain 1982; 9:23-6. 13. Auer RN, Siesjo BK. Biological differences between ischemia, hypoglycemia, and epilepsy. Ann Neurol 1988;24:699-707. 14. Maki Y, Semba A. Computed tomography of Sturge-Weber disease. Child's Brain 1979; 5: 51-61.
Ito et al: Sturge-Weber 477
Patients with Sturge-Weber disease with epilepsy refractory to medical therapy have been reported to develop slowly progressive neurological deficits and ultimately become moderately or severely disabled. We studied six patients with Sturge-Weber syndrome including its incomplete form. Three out of six patients with Sturge-Weber syndrome revealed evolution of calcified angioma on computed tomography. All of the three cases developed medically intractable seizures. Total and/or subtotal hemispherectomy was performed for these three cases. The surgery was effective for controlling seizures in all three cases except one with infantile spasm with hypsarrythmia on electroencephalogram who is still on anticovulsant. Although the unremitting deterioration in mental retardation and hemiparesis was not effectively prevented by the surgery possibly because the timing of surgery was delfl)'ed in one case, the surgery not only stopped the frequent medically-intractable seizures, but also dramatically prevented the psychomotor deterioration in the other case. Although the role of surgical treatment for the patients with Sturge-Weber syndrome remains poorly defined, one can expect excellent results if the indications for surgery are carefully analyzed and hemispherectomy is performed on an individual basis. Key words: Sturge-Weber disease, convulsive seizure, calcification, cerebral angioma, hemispherectomy. Ito M, Sato K, Ohnuki A, Uto A. Sturge- Weber disease: operative indications and surgical results. Brain Dev 1990;12:473-7
Although little is known of the clinical course and longterm prognosis of Sturge-Weber disease, it has been reported that about 30 to 40% of patients develop slowly progressive neurological deficits, and ultimately become moderately or severely disabled [1, 5, 7-9]. The deleterious effect of repeated seizures and chronic cerebral ischemia caused by cerebral angiomatosis on the developing brain is thought to be the underlying pathophysiology of the disease [7]. Neurosurgical intervention for the disease has been advocated in several institutions to control the intractable seizures and prevent the development of progressive neurological deficits [1,5,7-9]. We recently performed hemispherectomy in three patients with Sturge-Weber disease. In this paper, we discuss the operative indications and surgical results with respect to the natural history and outcome of the disease, and present
From the Department of Neurosurgery, J untendo University School of Medicine, Tokyo. Received for publication: February 17, 1990. Accepted for publication: May 9, 1990. Correspondence address: Dr. Masanori Ito, Department of Neurosurgery, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113, Japan.
an illustrative case.
PATIENT SELECTION AND SURGICAL INDICATIONS The neurological and radiological fmdings of six patients with Sturge-Weber disease are listed in Table 1. Neurosurgical intervention was not indicated for those in whom the convulsive seizures were being medically controlled, psychomotor development was not retarded, and no progression of calcified lesion was found on CT (patients 1, 2 and 3). We carried out surgical treatment for three patients (patients 4, 5 and 6) who were medically intractable and had psychomotor retardation. A 6-month-old male infant with Sturge-Weber disease (patient 4) [10] had intractable seizures and right hemiparesis for three months. On CT, the patient had cerebral atrophy and a calcified lesion in the left parieto-occipital lobe. The patient underwent excision of the lesion, by parietooccipital lobectomy. However, seizures could not be controlled postoperatively, and progression and extension of the calcified angiomatosis were observed on CT at 11 months of age. Therefore, left hemispherectomy was performed. A 3-month-old male infant (patient 5) with facial angioma at birth presented with infantile spasms
occasionally associated with tonic-clonic seizures. Compared with the CT finding at birth, CT showed progression of a band-like calcified lesion along the right frontal gyrus and frontal cortical atrophy. The seizures were not controlled by an exhaustive anticonvulsant regimen, and neck
Table I
fixation began to be impaired. A 5-year-old boy with atypical Sturge-Weber disease [11] (patient 6) underwent right subtotal hemispherectomy. The clinical course and surgical result of this patient are described separately as an illustrative case report.
Clinical data Age
Sex
Facial angioma
Onset
Seizure type
Response to medication
Neuro· logical deficit
1
8m
M
L
7m
Focal
Controlled
None
2
10m
M
R
10m
Focal
Controlled
3
3m
F
None
3m
Focal, IS
4
5m
M
L
3m
5
2m
M
R
6
4y
M
None
Patient
CT calcifications
CT atrophy
CT evolution
L-focal, spike
L-O
None
No
3
None
R-focal, negative spike
R&L-O
None
No
1.5
Controlled
None
RL polyspike& wave
R&L-PO
Lt-T,P
No
3
Focal
Intractable
Hemiparesis, psychomotor retardation
L-diffuse, slowing
L-F,T,P,O
Lt-F,T
Yes
6
3m
IS,focal
Intractable
Poor head fixation
Hypsarrhythmia
R-F
R-F
Yes
1.5
3y
Focal
Intractable
Psychomotor retardation
R-diffuse, spike wave
R-T,P,O
R-T,P,O
Yes
3
EEG
Follow· up (years)
m: months old, y: years old, M: male, F: female, L: left, R: right, IS: infantile spasm, F: frontal, T: temporal, P: pariental, 0: occipital.
Fig 1 Precontrast CT at 3 years of age shows a serpentine calcification in the right occipitallobe.
Fig 2 Precontrast CT scan at 4 years of age demonstrates extension of the calcified lesion the into temporal and parietal lobes. Note the enlargement of the trigone and inferior hom of the right lateral ventricle.
474 Brain & Development, Vol 12, No 5,1990
RESULTS Hemispherectomy or subtotal hemispherectomy was apparently effective for the control of medically intractable seizures in all three cases. The seizures disappeared postoperatively in all patients, and anticonvulsant administration has not been needed except in patient 5, who recently underwent surgery. Psychomotor retardation following onset of seizures was dramatically reversed immediately after subtotal hemispherectomy concomitant with the disappearance of seizures in two cases (patients 4 and 5). However, in patient 3, progression of mental retardation and loss of the motor function of the right fmgers and hand could not be prevented by the surgical management, probably because the patient already had right hemiparesis and cerebral atrophy, as shown by CT at 4 months of age.
motor development until the onset of convulsive seiZUres at 3 years. By age 4, the seizures had become increasingly intractable in spite of exhaustive anticonvulsant regimens. The patient was suffering convulsive attacks several times a day by 5 years of age, and during the one-year period, had become unable to sing, run, or count. Precontrast CT at 3 years of age revealed a typical fmding of Sturge-
ILLUSTRATIVE CASE REPORT A 3-year-old boy had shown completely normal psycho-
Fig 3 Axial MR image (SE 500/30) showing marked dilatation of the trigone and inferior horn of the right lateral ventricle.
Fig 4 Axial MR image (SE 2000/80) showing an area of high signal intensity in the thinned right tempordparietooccipitallobe. Note the signal intensity of the lesion is almost identical with that of cerebrospinal fluid.
Fig 5 A: Intraoperative photograph showing leptomeningeal angiomatosis in the right frontoparietal cortex after aspiration of cerebrospinal fluid from the dilated subarachnoid space. Band C: Photomicrographs of occipital cortical tissue showing extensive leptomeningeal angiomatosis and calcifications within the brain parenchyma. HE stain, x 50 (B) and xl 00 (C).
Ito et al: Sturge-Weber 475
Weber disease (serpentine calcified lesion) in the right occipital lobe (Fig 1). The lesion was not enhanced by contrast medium. Since the patient did not have facial angioma, he was diagnosed as having Sturge-Weber disease without facial nevus [11] or a form fruste variety of the disease. Precontrast CT at 4 years of age demonstrated extension of the calcified lesion into the temporal and parietal lobes concomitant with enlargement of the trigone and inferior horn of the right lateral ventricle (Fig 2). Tl-weighted MRI revealed marked dilatation of the trigone and inferior horn of the right lateral ventricle, while the T-2 weighted image showed an area of high signal intensity in the right temporoparietooccipitallobe, suggesting ischemic change in this region (Figs 3 and 4). Right carotid angiography revealed an avascular area and a lack of cortical vein visualization in the right temporoparietooccipital region. There was no visualization of deep veins such as the internal cerebral vein, basal vein, and vein of Galen. [1 23 I] IMP-SPECT revealed a marked reduction in blood flow in the right temporoparietooccipital lobe, corresponding to the area of high signal intensity signal on the T-2 weighted MRI image. Right temporoparietooccipital lobectomy, subtotal hemispherectomy, was carried out. The frontal lobe, thalamus, and basal ganglia were preserved. The postoperative course was uneventful. The patient has been free of seiZUres without the administration of anticonvulsants. Three months after the operation, the patient was able to sing, count, and run, and started going to Kindergarten. The intraoperative fmdings of patient 5 are shown in Fig 5A. After the cerebrospinal fluid was aspirated, the distended subarachnoid space collapsed and leptomeningeal angiomatosis was .observed in the atrophic right frontoparietal cortex. Histological fmdings of the case are shown in Fig 5B and C. There was extensive leptomeningeal angiomatosis and calcification within the brain parenchyma, both in the cortex and white matter. Neuronal atrophy, neuronal loss and gliosis were also found. DISCUSSION Natural history of Sturge-Weber disease The natural history of Sturge-Weber disease remains unknown. Long-term follow-up studies reported from the Mayo Clinic (31 cases) [8] and the Hospital for Sick Children in Toronto (41 cases) [9] indicated that 30 to 40% of patients with the disease had moderate to severe neurological deficits and epilepsy, and did poorly at home or were confined to institutions. It deserves special mention that patients in whom the onset of convulsive seizures was within the first year of life had severe neurological deficit [7, 9]. Nevertheless, variability in natural course of the disease has been reported such as delayed onset of neurological signs [6], and delays onset of sei-
476 Brain & Development, Vol 12, No 5,1990
zures at the age of 4 years which became refractory to medical therapy with marked visual symptomatology at 13 years of age [2]. Progressive nature of the disease Progressive calcification in the disease is thought to be caused by reduced blood supply to the involved hemisphere, which in turn leads to gliosis and atrophy of the brain parenchyma induced by chronic ischemic insult [7, 12]. The repeated convulsive seizures, which implicate abnormal excitation of the neural cells and relatively poor blood supply (pathologically enhanced energy consumption), may result in neuronal damage similar or identical to ischemic brain damage [13]. It is well-known that tram-track calcification on plain skull X-ray films usually appears in patients over the age of 2 years and is rarely demonstrated before the age of one [14], indicating the progressive nature of brain calcification. Serial CT has been reported to demonstrate evolution of calcified occipitallesion [2]. Progressive enlargement of the calcified lesions was clearly demonstrated on CT scan in three of our six cases. All three of these patients presented with medically intractable seiZUres. In contrast, the calcified lesions remained unchanged during at least one to two years of follow-up in the three patients in whom seizures were medically controlled. Positron emission tomography (PET) with 2-deoxy-2 [18] fluoro-D-glucose to measure local cerebral glucose metabolic rates for glucose [4] and/or 133-Xe single photon emission computed tomography (SPECT) to measure regional cerebral blood flow [3] have been suggested to reveal functional abnormalities that precede structural changed detected by CT in patients with Sturge-Weber syndrome. Subsequently, serial PET or SPECT studies can be used to assess the progression of functional cerebral impairment [3, 4] . Rationale for surgical treatment It seems reasonable to expect that surgical removal of the
leptomeningeal angiomatosis and underlying abnormally functioning gliotic cerebral cortex would eliminate the ischemic epileptic focus and prevent progression of ischemic convulsive brain damage [1, 5, 7, 8]. Hoffman et al [7] reported the results of seven hemispherectomies for infants with Sturge-Weber disease. They postulated that hemispherectomy must be undertaken if seizures begin in infancy, the disease is Unilateral, and the entire hemisphere is involved. Based upon their follow-up results for one to 13 years (median eight years), the younger the patient at the time of surgery, the higher the eventual IQ; in addition, an inverse correlation was noted between the duration of preoperative seizures and postoperative IQ [7]. Surgical treatment should be undertaken before irreversible organic brain damage develops. Early surgical intervention is strongly advocated if the epilepsy is considered to be medically intractable. Hoffman et al
[7] claimed that infantile cases presenting with intractable seizures should be operated on within the first year of life. In our case of rather late onset, subtotal hemispherectomy case, in a 4-year-old male (patient 6) was able to abolish intractable seizures and even reverse severe psychomotor retardation. Surgical method and results According to Falconer et al [5], Balder pioneered surgical intervention for cerebral angioma in the disease, and electrocoagulation of angiomatosis is reported to reduce the frequency of convulsive seizures. Peterman et al [8] reported that one of their four surgically treated patients showed an apparent increase in intelligence quotients after surgical excision, and seizures and behavioral problems decreased. Falconer and Rushworth [5] reported the results of five hemispherectomies for the disease, and concluded that surgery helped to abolish seizures. Hoffman et al [7] reported that hemiparesis in children operated upon early in infancy was surprisingly minimal. The late postoperative complication of superficial cerebral hemosiderosis due to repeated bleeding caused by a lack of adequate support for the remaining hemisphere is reported to develop in one-fourth to one-third of patients followed for long periods after an anatomically complete hemispherectomy [15]. However, this complication could be prevented by subtotal hemispherectomy, leaving in place the frontal and occipital lobes. In the present cases, parts of the frontal or occipital lobes were left unremoved. The area to be removed was determined by neuroimaging, i.e., a calcified lesion on CT, an area of low or no blood flow on SPECT or PET, and a high intensity area on T-2 weighted MRJ image, and the intraoperative macroscopic (microsurgical) appearance.
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